FORMATION AND RESOLUTION OF DOUBLE-STRAND BREAK INTERMEDIATES IN V(D)J REARRANGEMENT
FORMATION AND RESOLUTION OF DOUBLE-STRAND BREAK INTERMEDIATES IN V(D)J REARRANGEMENT
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DOI：
10.1101/gad.9.19.2409
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发表时间：
1995-10-01
影响因子：
10.5
通讯作者：
GELLERT, M
中科院分区：
文献类型：
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作者：
RAMSDEN, DA;GELLERT, M
最近描述的一种前b细胞系可以在高温下诱导其免疫球蛋白轻链位点主动重排。我们用这个细胞系来确定V(D)J重排产生的双链断裂的命运。诱导后，30% ~ 40%的kappa基因座J kappa 1信号端断裂。J kappa 1编码端可以检测到，但频率要低10到100倍。共价闭合的（发夹）和开放的、钝的、加工过的编码端都被观察到。涉及J kappa 1的编码结与J kappa 1信号端具有相似的积累动力学，这表明编码端可以快速有效地分解为编码结，而信号端大多保持不连接。当细胞回到低温状态时，信号端迅速连接。这些结果支持了信号断续端和发夹编码端是V(D)J重组的真实中间体的模型。发夹编码端似乎被迅速打开、处理并分解为编码连接，而信号端连接显然与编码端连接不耦合，并且速度要慢得多。信号连接的有效形成可能需要细胞周期的进展或重组机制的下调。
A recently described pre-B cell line can be induced at high temperature to actively rearrange its immunoglobulin light-chain loci. We used this cell line to determine the fate of double-strand breaks generated by V(D)J rearrangement. After induction, 30%-40% of kappa loci had broken J kappa 1 signal ends. J kappa 1-coding ends were detectable, but 10- to 100-fold less frequent. Both covalently closed (hairpin) and open, blunt, processed coding ends were observed. Coding junctions involving J kappa 1 accumulated with similar kinetics as J kappa 1 Signal ends, arguing that coding ends can be resolved quickly and efficiently to coding junctions, whereas signal ends remain mostly unjoined. Signal ends are then joined rapidly when cells are returned to the low temperature. These results support the model that broken signal ends and hairpin coding ends are authentic intermediates in V(D)J recombination. It appears that hairpin coding ends are rapidly opened, processed, and resolved to coding junctions, whereas joining of signal ends is clearly uncoupled from the joining of coding ends and can be much slower. Efficient formation of signal junctions may require cell cycle progression, or down-regulation of the recombination machinery.